Relevant parameters of the voiced fricative /z/

No abstract

Relevant parameters of the voiced fricative /z/

No abstract

Alternative microbial technologies for micropollutant removal from secondary wastewater effluent

Trace organic pollutants, also called micropollutants, are endangering the quality of our drinking water resources. Pharmaceuticals such as painkillers, antibiotics and contraceptives, biocides such as insect repellants or anti-septic agents in toothpaste are just a few examples of the thousands of different substances used in medicine and personal care. Thanks to the advances in analytical technology, it is possible to detect and measure nanogram-per-liter quantities of these organic pollutants. This makes it possible to study their occurrence, effect and mitigation. In the search of mitigation technologies to remove these micropollutants before discharge into the environment, two techniques were investigated in this doctoral thesis. The first technique is an existing wastewater treatment process, nitrification, applied in an unconventional way to remove endocrine disrupting compounds. The second technique is a novel process using biogenic manganese oxides (BioMnOx), developed for the oxidative removal of pharmaceuticals and biocides. The concept of biogenic metals was explored further by the application of bio-palladium (Bio-Pd) for the dehalogenation of iodinated contrast media used in medical imaging. It was clearly shown that nitrifiers, more specifically ammonia-oxidizing bacteria (AOB) are able to biologically degrade 17α-ethinylestradiol (EE2) and the process was engineered in an aerated submerged fixed bed reactor (FBR), at μg L-1 and sub-μg L-1 concentrations. An interesting outcome for further implementation of nitrification as a tertiary treatment is the robustness of the nitrifying community. The technological application of BioMnOx in a membrane bioreactor (MBR) showed the removal of more than 60% of 14 out of 29 micropollutants, detected at ng-μg L-1: diclofenac (86%), triclosan (>78%), chlorophene (>89%), naproxen (>95%), diuron (>94%), codeine (>93%), dihydrocodeine (41%), morphine (60%), mecoprop (>81%), N-acetyl-sulfamethoxazole (92%), iopromide (68%), iomeprol (63%) and iohexol (72%) and clarithromycin (75%). Bio-Pd for the catalytic dehalogenation of the iodinated X-ray contrast media (ICM) iomeprol, iopromide, iohexol and diatrizoate was successfully applied in a Bio-Pd-MBR with in situ H2-production to supply the Pd-catalyst with molecular hydrogen. The novel finding here was that in situ H2 production by anaerobic bacteria was an excellent alternative to supply the Bio-Pd catalyst with molecular hydrogen